Mitchell got his degree in biology
from Utah State University, he worked for the USDA
for some years.
And then when we my laboratory got
started on doing cannabis research, he calls me up
and he said, I'm interested, are you taking graduate students?
And he has been one of the top PhD graduate students
I've had in my career.
With his help, we've been able to test a lot of hypotheses
and he's going to show you some of the stuff
that we've been doing now.
Thanks.
You guys hear me in the back?
OK.
Yeah so like Bruce said, I'll give
a little bit of an overview of some of the things
that we've been doing, this is in no way comprehensive.
We've got a lot of balls in the air right now,
but we'll try to give you an idea of what we're working on
up at Utah State.
So I'll start out by talking about some water stress trials
that we've done, a little bit about the CBD
and THC production in the plant, and then I'll
touch a little bit on nutrition as well.
So one of the big questions with hemp especially here
in Utah is what sort of drought can it handle?
And we are set up at our lab with the system that
allows us to very precisely apply drought stress
and measure the plant's response to that drought stress.
So the way that this system works
is we've got 16 buckets there, they're all
loaded onto what basically amounts to a digital scale,
they're sealed on the top and so any change in weight
throughout the day is water moving
from the soil through the plant into the air.
And from this we can get an idea of how much they're transpiring
and how much photosynthesis they're doing,
and I'll talk about that in a second.
So we've got this system set up to a data logger that
records all of the values, we send it to a computer,
and then we can generate some useful data.
So this is what it looks like after we get it
from the computer.
So we've got transpiration there on the y-axis,
and again, that's just water moving
from the soil through the plant into the atmosphere.
And each of these represents one day,
so the sum of each of those points
equals the daily transpiration rate for that plant.
And we can see this decline here over time,
and that's a result of dry down.
So when the plant runs out of water,
it obviously has no more water to take up and transpire,
and so what does that mean exactly?
Well, we carried out this study, we kept one group of plants
well watered and then we really hammered another set of plants
and you can see this plant right here is wilted very bad.
And they were like that for about two or three days.
We ran some initial trials where we
did a little bit more mild stress,
and the plants responded just fine.
So we wanted to follow up and really hit
them and see how they respond.
And this is what we saw with our initial trials is,
after watering, the plant came back, it looked fine,
but it wasn't up to the standards
that it would have been had it kept its well watered status.
And one of the cool technologies that we were able to use
is infrared imaging to detect water stress.
So water moving through the plant
is similar to sweat on humans, so it keeps them cool.
And so plants who aren't moving as much water
through their leaves are going to heat up.
So we can use this technology to detect water stress before it
becomes visually apparent.
So what does that mean exactly?
Why do we care about transpiration?
The reason is transpiration is very tightly correlated
with photosynthesis and photosynthesis is very tightly
correlated with yield.
Water is moving out of the same holes
that CO2 is moving in through, and so it's a balancing act
and so if you can keep those holes open longer and wider,
then you allow more CO2 to come in
and that results in a higher yield at the end of the day.
So then we decided to look at the other end of the spectrum.
You hear pretty often that hemp doesn't
like to get its feet wet and so we thought we'd test that out.
We plugged up some of these buckets, it's hard to see here
but this is in standing water, we had three or four buckets
that we were able to plug up really nicely
and get standing water in.
One of the big things that we saw was disease,
they were in standing water for about four days
before they started to wilt like this
and even after draining them they were gone.
So two of the big ones that we've been seeing
are pythium and fusarium, and here's
how the transpiration looked during this trial.
So we had these flooded plants that
stayed fine for about three or four days
while they were in standing water
and then they started to decline as the roots started
to rot away basically.
But what was interesting is this saturated group.
So this was the group that we weren't able to get plugged
very tightly, but we were still able to keep
the soil constantly moist, and as you can see,
it did just as fine as the controls.
I guess I'll change gears a little bit
and talk about CBD and THC and what
we've been seeing in our lab.
So one of the claims is that, and it's backed up
by science is that, secondary metabolism
increases under stress and secondary metabolism
is basically the production of compounds that aren't
necessary for growth and development,
but they are necessary for the survival of the plant.
So they can deter pests, it's basically
like a human immune system.
And so we wanted to see if the drought
stress would increase the CBD and the THC in the leaves.
One of the issues that we had with this trial
is we had them under 18 hours.
So we couldn't flower them out, so we
were limited to the leaves.
But what we saw in the leaves was really no change,
the CBD stayed about constant and the THC
was so low that it's hard to draw any definitive conclusions
about that.
We do have a trial going right now in the growth chamber,
we will basically replicate this exactly,
but with flowering plants.
And so we can see how CBD and THC are affected by drought.
So on the topic of stress, we ran three replicate trials,
everything was the exact same between the three trials,
but we saw a really, really low yield in the first trial
compared to the second and the third.
And what we thought might have happened
was some early stress in that first trial.
We haven't been able to positively identify anything
yet, but it's the only thing that makes sense.
So we're looking at possible water and nutrient stress
during that first trial.
So as you could see, we saw an increase in yield
as the plants got less stressed and we saw a decrease
in the percent THC and CBD.
When you multiply these two values together
you can come up with an absolute amount of CBD and THC
in the plant and what we see is it's about the same.
So the plants are basically concentrating they're
cannabinoids under stress.
But when it comes out at the end of the day,
they're producing about the same amount.
One of the other things that we've seen on occasion
is the possibility for CBD and THC to decline at some point.
So we see here at about 40 days we peak in our CBD and THC
levels and then they drop off after that.
Like I said, we're seeing it occasionally,
but it's not exactly clear what could
be causing that at this time.
But that's something we are working on.
But one thing that we've seen time and time
again is this constant CBD to THC ratio.
It's constant from the leaves to the flowers
at any point throughout the plant's lifecycle.
The best that we've been seeing right now is about 30 to 1,
we haven't really seen any of these magic 60 to 1 genetics.
That's not to say they don't exist,
but this is typically what we've been seeing.
So this was a field here in Utah after a frost event
that happened early October.
We had two nights where we got really, really cold
and so I drove down and I took some samples
to see how the plants responded.
And so this line here is the day of the hard freeze
and unfortunately, abacus was harvested
before this but these two cultivars
both declined in CBD and THC.
And this just supports our idea that there
is the potential for those to decline at some point,
it's just a matter of figuring out what can cause that.
Notably, the plants looked fine.
I mean we got down to 28 degrees, low 20s,
and the plants looked more or less unharmed.
So one of the things we've learned
is that this plant is hardy, I mean,
this is a bulletproof plant.
So it'll be interesting to see what limits we can push it to.
OK, last topic I'll just touch on nutrition.
Like Bruce mentioned, there's all sorts
of claims about magic fertilizers,
put this on your plant, put that on your plant,
it'll grow two legs and two arms.
But one of the big claims within the cannabis world
is high phosphorus, especially during flowering.
And so we decided to test this, and we did it
in very controlled environments so we can really
get at is it the nutrition or is there something else going on.
And we went from about 70 pounds an acre,
which is a little under what they recommend for corn,
up to just an outrageous amount, 300 pounds per acre
and we saw no difference.
The conclusions you can draw from this
is, fertilize it like you would any other plant.
There's no special mix that's going to make cannabis grow
any better than anything else.
We tested the cannabinoids and again everything came out
exactly identical, THC came out identical, CBD the same.
And again we see that constant CBD to THC ratio.
So we've got a lot going on in the lab.
We're certain to have a lot more information coming out
over the next few years.
We are working very hard to try and understand this plant,
so it'll be a lot of fun to see what we can get done up there.
Thanks.